Well, the “Frontline Campaign” completed, at least. I’m not sure the other modes are completable? Anyway, I completed it.
And good grief was it hard. It plays out as a grid of islands, each one like a miniature normal mode, only there are a fixed number of targets to take out. Once you’ve done that, you move onto taking over another island, heading from the bottom left of the map to the top right. As you do so, the enemy head from the top right to the bottom left.
It starts out pretty easy, but once the enemy reaches you, a Baron – a highly powered up fighter plane – seeks you out on the level and really makes it difficult. I found taking him out needed to be top priority.
The final level on the map was utter chaos with many, many retreats due to being almost shot to pieces. Eventually I took everything out and won the war.